Expansible lap



A. RlNGZELLl May 4, 1948.

EXPANSIBLE LAP Filed Feb. 8f 1945 aff/074726@ Patented May 4, 194g j n,

UNITED smrea- This invention rentes@ iapslor. nisiung tools' such as` commonly'used for lapping or'polishi'ng surfaces of holesv in. work'V pieces, or'the like.

The objects of-th-is invention are to provide an improved tool of th'e character indicated which will be particularlyv simple `inconstruction and economical to manufacture, and which will be durable and efficient in use; to provide a lap having a cylindrical portion with outlets in the sides thereof and having an expansible-jand replaceable insert or plug with means for expanding the same; to provide a lap which may beieasily and quickly adjusted without removing the same from'the drill or-fmachinef'too'l; to providefa lap having means for supplying abrasive material* from a central chamber; and to provide such other novel features and improvements in operation as will be described more fully hereinafter.

In the accompanying drawings illustrating this invention,

Fig. 1 is an expanded view showing the several parts of the lap;

Fig. 2 is a side view with parts broken away to show the interior construction;

Fig. 3 is a cross sectional view taken on the line 3 3 of Fig. 1;

Fig. 4 is a cross sectional view taken on the line i-ll of Fig. 2';

Fig. 5 is a side view partly in section showing the lap in operating position in a drill press; and

Fig. 6 is a detail showing a modiiiecl form of compressing or expanding pin.

In the particular form of the invention as shown in these drawings, the lap comprises a rod 'I which is shouldered at its upper end as shown at B for engagement with the drill chuck 9. The lower end of the rod has a longitudinal bore or recess I0 which may conveniently be formed by drilling. The sides of the cylindrical portion have a plurality of longitudinal slots II which terminate at a short distance from the end of the lap. An expandible and replaceable plug I2 is inserted in the hole IIJ and engages with the bottom of the hole II as shown in Fig. 2. This plug may be made of any suitable material, but preferably of rubber impregnated with an abrading or polishing substance such as emery or the like. A pin I 3 which is knurled as shown at I 4 ts tightly in th'e end of the lap and engages with the plug IZ.

This pin serves to compress and expand the plug I2 which in turn eXpands or bulges out the,

segments or lands I'I of the lap between the slits II. This provides a desirable barrel shaped work engaging surface as will readily be seen from Figs. 2 and 5.

7 claims.0 o1. .signin` viis/magi the l rap. is tof foei-used.' V1l-.fis prfrant; placed' in. adrill chuck'land,'extends through a hole.` I 5. in a work .pice asv indicated at" |62 for the.

purpose. of lapping .th' esl: otsuchfhole. The

plug or cartridge..l2..mayfbe Acompressed tosuelgg-v a degree. thatportionsthereofmwill be extruded` through theslts I-I sothat theabradi11g-orpolishinglmaterial, (will. come in contact with the sur iac'agcffthe.ll'iolelf-r Additional. lapping material may also be suppliedinthe usual manner. Afterv the lap'. hasbeen usedfffor; a given lengthfof time,

it fis frequentlyv desired. to expand or enlarge ,thea

saine..` In the presentinstance, this is readily accomplished .bympvingzthe drill Achuck 9 down-5A `Vwaiily until.the..end of thev pin I3. engages withl the bed plate i8 and may be forced further inwardly by pressure against the bed plate.

After the impregnated plug or insert I2 has been compressed or expanded several times for adjusting the size of the lap, it may be desirable to remove the same and insert a new plug. This may be readily done, and the new plug will provide a further supply of emery or abrasive material. The longitudinal or straight knurling of the adjusting pin permits it to be adjusted or replaced in the lap with suflicient friction to hold it in adjusted positions. This provides means whereby the lap may be quickly adjusted without being removed from the machine tool,

The pin I3 is shown withI a flat or square engaging yend which is desirable if the plug I2 is formed of rubber, but in some instances, I may use a pin I9 as shown in Fig. 6 with a sharp or pointed end 20 for engagement with the plug. This may be desirable if the plug is made of wood, or. other similar material in which case the sharpened end will serve to more readily expand the end of the plug.

Having thus described my invention whichf however, may be modified within the terms of the following claims, what I claim is:

i. A lap, comprising a rod having a recess at one end with longitudinal slits terminating shortV to be pressed against the plug whereby the sides of the cylindrical portion may be expanded and portions of the plug may be forced out through said openings so that the emery may come in contact with the surface of the hole being acted upon.

4. In a lap, the combination of a tubular body*k having a plurality of substantially longitudinal slits which terminate at a distance from the ends thereof and provide circumferentially arranged Work engaging lands forming a lapping portion and having an abutment formed integrally therein, an expansible insert formed of resilient material in said body and engaging said abutment, and expanding means engaging with the end of the tubular body and with said expansible insert for compressing the insert and expanding the sides of the body to adjust the effective diameter of the lapping -portion of the lapl 5. In a lap, the combination of a rod portion having a shoulder at one end and having a longitudinal recess at the opposite end with slits extending through the walls of the recess, to provide a plurality of work engaging lands, a pin extending into the recess and having a knurled portion engaging with the outer end thereof, and resilient expansible means between the inner end of the pin and the bottom of the recess adapted to be compressed and expanded by the pin for expanding the side Walls of the recess to provide a barrel shaped work engaging surace.

6. The combination with a press, of a lap having a shouldered end engaging with the chuck of the press and havinga downwardly extending integrally formed cyclindrical portion pro- `vided with slits forming a plurality of expansible lands, an insert formed of resilient material in the cylindrical portion, an expanding pin fitting tightly in the cylindrical portion and extending therefrom which is adapted to engage with the insert and with the bed of the press, the arrangement being such that the lands may be expanded by forcing the expanding member against the bed whereby the lap may be adjusted without being removed from the press.

7. A device, as per claim 2, in which the pin has a sharpened engaging end, as described.

ARTHUR RINGZELLI.

REFERENCES CITED The following references are of record in the ille of this patent:

3 UNITED STATES PATENTS Number Name Date 1,352,805 Fuller Sept. 14, 1920 Y 2,084,175 Zimmerman June l5, 1937 35 2,298,367 Claude Oct. 13, 1942 

